Commit 100719dc authored by Tom Zanussi's avatar Tom Zanussi Committed by Steven Rostedt (VMware)

tracing: Add simple expression support to hist triggers

Add support for simple addition, subtraction, and unary expressions
(-(expr) and expr, where expr = b-a, a+b, a+b+c) to hist triggers, in
order to support a minimal set of useful inter-event calculations.

These operations are needed for calculating latencies between events
(timestamp1-timestamp0) and for combined latencies (latencies over 3
or more events).

In the process, factor out some common code from key and value
parsing.

Link: http://lkml.kernel.org/r/9a9308ead4fe32a433d9c7e95921fb798394f6b2.1516069914.git.tom.zanussi@linux.intel.comSigned-off-by: default avatarTom Zanussi <tom.zanussi@linux.intel.com>
[kbuild test robot fix, add static to parse_atom()]
Signed-off-by: default avatarFengguang Wu <fengguang.wu@intel.com>
[ Replaced '//' comments with normal /* */ comments ]
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent 2ece94fb
......@@ -32,6 +32,13 @@ typedef u64 (*hist_field_fn_t) (struct hist_field *field, void *event,
#define HIST_FIELD_OPERANDS_MAX 2
#define HIST_FIELDS_MAX (TRACING_MAP_FIELDS_MAX + TRACING_MAP_VARS_MAX)
enum field_op_id {
FIELD_OP_NONE,
FIELD_OP_PLUS,
FIELD_OP_MINUS,
FIELD_OP_UNARY_MINUS,
};
struct hist_var {
char *name;
struct hist_trigger_data *hist_data;
......@@ -48,6 +55,8 @@ struct hist_field {
struct hist_field *operands[HIST_FIELD_OPERANDS_MAX];
struct hist_trigger_data *hist_data;
struct hist_var var;
enum field_op_id operator;
char *name;
};
static u64 hist_field_none(struct hist_field *field, void *event,
......@@ -98,6 +107,41 @@ static u64 hist_field_log2(struct hist_field *hist_field, void *event,
return (u64) ilog2(roundup_pow_of_two(val));
}
static u64 hist_field_plus(struct hist_field *hist_field, void *event,
struct ring_buffer_event *rbe)
{
struct hist_field *operand1 = hist_field->operands[0];
struct hist_field *operand2 = hist_field->operands[1];
u64 val1 = operand1->fn(operand1, event, rbe);
u64 val2 = operand2->fn(operand2, event, rbe);
return val1 + val2;
}
static u64 hist_field_minus(struct hist_field *hist_field, void *event,
struct ring_buffer_event *rbe)
{
struct hist_field *operand1 = hist_field->operands[0];
struct hist_field *operand2 = hist_field->operands[1];
u64 val1 = operand1->fn(operand1, event, rbe);
u64 val2 = operand2->fn(operand2, event, rbe);
return val1 - val2;
}
static u64 hist_field_unary_minus(struct hist_field *hist_field, void *event,
struct ring_buffer_event *rbe)
{
struct hist_field *operand = hist_field->operands[0];
s64 sval = (s64)operand->fn(operand, event, rbe);
u64 val = (u64)-sval;
return val;
}
#define DEFINE_HIST_FIELD_FN(type) \
static u64 hist_field_##type(struct hist_field *hist_field, \
void *event, \
......@@ -147,6 +191,7 @@ enum hist_field_flags {
HIST_FIELD_FL_TIMESTAMP = 1 << 10,
HIST_FIELD_FL_TIMESTAMP_USECS = 1 << 11,
HIST_FIELD_FL_VAR = 1 << 12,
HIST_FIELD_FL_EXPR = 1 << 13,
};
struct var_defs {
......@@ -258,6 +303,8 @@ static const char *hist_field_name(struct hist_field *field,
field_name = hist_field_name(field->operands[0], ++level);
else if (field->flags & HIST_FIELD_FL_TIMESTAMP)
field_name = "common_timestamp";
else if (field->flags & HIST_FIELD_FL_EXPR)
field_name = field->name;
if (field_name == NULL)
field_name = "";
......@@ -519,12 +566,104 @@ static const char *get_hist_field_flags(struct hist_field *hist_field)
return flags_str;
}
static void expr_field_str(struct hist_field *field, char *expr)
{
strcat(expr, hist_field_name(field, 0));
if (field->flags) {
const char *flags_str = get_hist_field_flags(field);
if (flags_str) {
strcat(expr, ".");
strcat(expr, flags_str);
}
}
}
static char *expr_str(struct hist_field *field, unsigned int level)
{
char *expr;
if (level > 1)
return NULL;
expr = kzalloc(MAX_FILTER_STR_VAL, GFP_KERNEL);
if (!expr)
return NULL;
if (!field->operands[0]) {
expr_field_str(field, expr);
return expr;
}
if (field->operator == FIELD_OP_UNARY_MINUS) {
char *subexpr;
strcat(expr, "-(");
subexpr = expr_str(field->operands[0], ++level);
if (!subexpr) {
kfree(expr);
return NULL;
}
strcat(expr, subexpr);
strcat(expr, ")");
kfree(subexpr);
return expr;
}
expr_field_str(field->operands[0], expr);
switch (field->operator) {
case FIELD_OP_MINUS:
strcat(expr, "-");
break;
case FIELD_OP_PLUS:
strcat(expr, "+");
break;
default:
kfree(expr);
return NULL;
}
expr_field_str(field->operands[1], expr);
return expr;
}
static int contains_operator(char *str)
{
enum field_op_id field_op = FIELD_OP_NONE;
char *op;
op = strpbrk(str, "+-");
if (!op)
return FIELD_OP_NONE;
switch (*op) {
case '-':
if (*str == '-')
field_op = FIELD_OP_UNARY_MINUS;
else
field_op = FIELD_OP_MINUS;
break;
case '+':
field_op = FIELD_OP_PLUS;
break;
default:
break;
}
return field_op;
}
static void destroy_hist_field(struct hist_field *hist_field,
unsigned int level)
{
unsigned int i;
if (level > 2)
if (level > 3)
return;
if (!hist_field)
......@@ -534,6 +673,7 @@ static void destroy_hist_field(struct hist_field *hist_field,
destroy_hist_field(hist_field->operands[i], level + 1);
kfree(hist_field->var.name);
kfree(hist_field->name);
kfree(hist_field);
}
......@@ -554,6 +694,9 @@ static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data,
hist_field->hist_data = hist_data;
if (flags & HIST_FIELD_FL_EXPR)
goto out; /* caller will populate */
if (flags & HIST_FIELD_FL_HITCOUNT) {
hist_field->fn = hist_field_counter;
goto out;
......@@ -626,6 +769,257 @@ static void destroy_hist_fields(struct hist_trigger_data *hist_data)
}
}
static struct ftrace_event_field *
parse_field(struct hist_trigger_data *hist_data, struct trace_event_file *file,
char *field_str, unsigned long *flags)
{
struct ftrace_event_field *field = NULL;
char *field_name, *modifier, *str;
modifier = str = kstrdup(field_str, GFP_KERNEL);
if (!modifier)
return ERR_PTR(-ENOMEM);
field_name = strsep(&modifier, ".");
if (modifier) {
if (strcmp(modifier, "hex") == 0)
*flags |= HIST_FIELD_FL_HEX;
else if (strcmp(modifier, "sym") == 0)
*flags |= HIST_FIELD_FL_SYM;
else if (strcmp(modifier, "sym-offset") == 0)
*flags |= HIST_FIELD_FL_SYM_OFFSET;
else if ((strcmp(modifier, "execname") == 0) &&
(strcmp(field_name, "common_pid") == 0))
*flags |= HIST_FIELD_FL_EXECNAME;
else if (strcmp(modifier, "syscall") == 0)
*flags |= HIST_FIELD_FL_SYSCALL;
else if (strcmp(modifier, "log2") == 0)
*flags |= HIST_FIELD_FL_LOG2;
else if (strcmp(modifier, "usecs") == 0)
*flags |= HIST_FIELD_FL_TIMESTAMP_USECS;
else {
field = ERR_PTR(-EINVAL);
goto out;
}
}
if (strcmp(field_name, "common_timestamp") == 0) {
*flags |= HIST_FIELD_FL_TIMESTAMP;
hist_data->enable_timestamps = true;
if (*flags & HIST_FIELD_FL_TIMESTAMP_USECS)
hist_data->attrs->ts_in_usecs = true;
} else {
field = trace_find_event_field(file->event_call, field_name);
if (!field || !field->size) {
field = ERR_PTR(-EINVAL);
goto out;
}
}
out:
kfree(str);
return field;
}
static struct hist_field *parse_atom(struct hist_trigger_data *hist_data,
struct trace_event_file *file, char *str,
unsigned long *flags, char *var_name)
{
struct ftrace_event_field *field = NULL;
struct hist_field *hist_field = NULL;
int ret = 0;
field = parse_field(hist_data, file, str, flags);
if (IS_ERR(field)) {
ret = PTR_ERR(field);
goto out;
}
hist_field = create_hist_field(hist_data, field, *flags, var_name);
if (!hist_field) {
ret = -ENOMEM;
goto out;
}
return hist_field;
out:
return ERR_PTR(ret);
}
static struct hist_field *parse_expr(struct hist_trigger_data *hist_data,
struct trace_event_file *file,
char *str, unsigned long flags,
char *var_name, unsigned int level);
static struct hist_field *parse_unary(struct hist_trigger_data *hist_data,
struct trace_event_file *file,
char *str, unsigned long flags,
char *var_name, unsigned int level)
{
struct hist_field *operand1, *expr = NULL;
unsigned long operand_flags;
int ret = 0;
char *s;
/* we support only -(xxx) i.e. explicit parens required */
if (level > 3) {
ret = -EINVAL;
goto free;
}
str++; /* skip leading '-' */
s = strchr(str, '(');
if (s)
str++;
else {
ret = -EINVAL;
goto free;
}
s = strrchr(str, ')');
if (s)
*s = '\0';
else {
ret = -EINVAL; /* no closing ')' */
goto free;
}
flags |= HIST_FIELD_FL_EXPR;
expr = create_hist_field(hist_data, NULL, flags, var_name);
if (!expr) {
ret = -ENOMEM;
goto free;
}
operand_flags = 0;
operand1 = parse_expr(hist_data, file, str, operand_flags, NULL, ++level);
if (IS_ERR(operand1)) {
ret = PTR_ERR(operand1);
goto free;
}
expr->flags |= operand1->flags &
(HIST_FIELD_FL_TIMESTAMP | HIST_FIELD_FL_TIMESTAMP_USECS);
expr->fn = hist_field_unary_minus;
expr->operands[0] = operand1;
expr->operator = FIELD_OP_UNARY_MINUS;
expr->name = expr_str(expr, 0);
return expr;
free:
destroy_hist_field(expr, 0);
return ERR_PTR(ret);
}
static int check_expr_operands(struct hist_field *operand1,
struct hist_field *operand2)
{
unsigned long operand1_flags = operand1->flags;
unsigned long operand2_flags = operand2->flags;
if ((operand1_flags & HIST_FIELD_FL_TIMESTAMP_USECS) !=
(operand2_flags & HIST_FIELD_FL_TIMESTAMP_USECS))
return -EINVAL;
return 0;
}
static struct hist_field *parse_expr(struct hist_trigger_data *hist_data,
struct trace_event_file *file,
char *str, unsigned long flags,
char *var_name, unsigned int level)
{
struct hist_field *operand1 = NULL, *operand2 = NULL, *expr = NULL;
unsigned long operand_flags;
int field_op, ret = -EINVAL;
char *sep, *operand1_str;
if (level > 3)
return ERR_PTR(-EINVAL);
field_op = contains_operator(str);
if (field_op == FIELD_OP_NONE)
return parse_atom(hist_data, file, str, &flags, var_name);
if (field_op == FIELD_OP_UNARY_MINUS)
return parse_unary(hist_data, file, str, flags, var_name, ++level);
switch (field_op) {
case FIELD_OP_MINUS:
sep = "-";
break;
case FIELD_OP_PLUS:
sep = "+";
break;
default:
goto free;
}
operand1_str = strsep(&str, sep);
if (!operand1_str || !str)
goto free;
operand_flags = 0;
operand1 = parse_atom(hist_data, file, operand1_str,
&operand_flags, NULL);
if (IS_ERR(operand1)) {
ret = PTR_ERR(operand1);
operand1 = NULL;
goto free;
}
/* rest of string could be another expression e.g. b+c in a+b+c */
operand_flags = 0;
operand2 = parse_expr(hist_data, file, str, operand_flags, NULL, ++level);
if (IS_ERR(operand2)) {
ret = PTR_ERR(operand2);
operand2 = NULL;
goto free;
}
ret = check_expr_operands(operand1, operand2);
if (ret)
goto free;
flags |= HIST_FIELD_FL_EXPR;
flags |= operand1->flags &
(HIST_FIELD_FL_TIMESTAMP | HIST_FIELD_FL_TIMESTAMP_USECS);
expr = create_hist_field(hist_data, NULL, flags, var_name);
if (!expr) {
ret = -ENOMEM;
goto free;
}
expr->operands[0] = operand1;
expr->operands[1] = operand2;
expr->operator = field_op;
expr->name = expr_str(expr, 0);
switch (field_op) {
case FIELD_OP_MINUS:
expr->fn = hist_field_minus;
break;
case FIELD_OP_PLUS:
expr->fn = hist_field_plus;
break;
default:
goto free;
}
return expr;
free:
destroy_hist_field(operand1, 0);
destroy_hist_field(operand2, 0);
destroy_hist_field(expr, 0);
return ERR_PTR(ret);
}
static int create_hitcount_val(struct hist_trigger_data *hist_data)
{
hist_data->fields[HITCOUNT_IDX] =
......@@ -648,36 +1042,16 @@ static int __create_val_field(struct hist_trigger_data *hist_data,
char *var_name, char *field_str,
unsigned long flags)
{
struct ftrace_event_field *field = NULL;
char *field_name;
struct hist_field *hist_field;
int ret = 0;
field_name = strsep(&field_str, ".");
if (field_str) {
if (strcmp(field_str, "hex") == 0)
flags |= HIST_FIELD_FL_HEX;
else {
ret = -EINVAL;
hist_field = parse_expr(hist_data, file, field_str, flags, var_name, 0);
if (IS_ERR(hist_field)) {
ret = PTR_ERR(hist_field);
goto out;
}
}
if (strcmp(field_name, "common_timestamp") == 0) {
flags |= HIST_FIELD_FL_TIMESTAMP;
hist_data->enable_timestamps = true;
} else {
field = trace_find_event_field(file->event_call, field_name);
if (!field || !field->size) {
ret = -EINVAL;
goto out;
}
}
hist_data->fields[val_idx] = create_hist_field(hist_data, field, flags, var_name);
if (!hist_data->fields[val_idx]) {
ret = -ENOMEM;
goto out;
}
hist_data->fields[val_idx] = hist_field;
++hist_data->n_vals;
++hist_data->n_fields;
......@@ -765,8 +1139,8 @@ static int create_key_field(struct hist_trigger_data *hist_data,
struct trace_event_file *file,
char *field_str)
{
struct ftrace_event_field *field = NULL;
struct hist_field *hist_field = NULL;
unsigned long flags = 0;
unsigned int key_size;
int ret = 0;
......@@ -781,60 +1155,24 @@ static int create_key_field(struct hist_trigger_data *hist_data,
key_size = sizeof(unsigned long) * HIST_STACKTRACE_DEPTH;
hist_field = create_hist_field(hist_data, NULL, flags, NULL);
} else {
char *field_name = strsep(&field_str, ".");
if (field_str) {
if (strcmp(field_str, "hex") == 0)
flags |= HIST_FIELD_FL_HEX;
else if (strcmp(field_str, "sym") == 0)
flags |= HIST_FIELD_FL_SYM;
else if (strcmp(field_str, "sym-offset") == 0)
flags |= HIST_FIELD_FL_SYM_OFFSET;
else if ((strcmp(field_str, "execname") == 0) &&
(strcmp(field_name, "common_pid") == 0))
flags |= HIST_FIELD_FL_EXECNAME;
else if (strcmp(field_str, "syscall") == 0)
flags |= HIST_FIELD_FL_SYSCALL;
else if (strcmp(field_str, "log2") == 0)
flags |= HIST_FIELD_FL_LOG2;
else if (strcmp(field_str, "usecs") == 0)
flags |= HIST_FIELD_FL_TIMESTAMP_USECS;
else {
ret = -EINVAL;
goto out;
}
}
if (strcmp(field_name, "common_timestamp") == 0) {
flags |= HIST_FIELD_FL_TIMESTAMP;
hist_data->enable_timestamps = true;
if (flags & HIST_FIELD_FL_TIMESTAMP_USECS)
hist_data->attrs->ts_in_usecs = true;
key_size = sizeof(u64);
} else {
field = trace_find_event_field(file->event_call, field_name);
if (!field || !field->size) {
ret = -EINVAL;
hist_field = parse_expr(hist_data, file, field_str, flags,
NULL, 0);
if (IS_ERR(hist_field)) {
ret = PTR_ERR(hist_field);
goto out;
}
if (is_string_field(field))
key_size = MAX_FILTER_STR_VAL;
else
key_size = field->size;
}
key_size = hist_field->size;
}
hist_data->fields[key_idx] = create_hist_field(hist_data, field, flags, NULL);
if (!hist_data->fields[key_idx]) {
ret = -ENOMEM;
goto out;
}
hist_data->fields[key_idx] = hist_field;
key_size = ALIGN(key_size, sizeof(u64));
hist_data->fields[key_idx]->size = key_size;
hist_data->fields[key_idx]->offset = key_offset;
hist_data->key_size += key_size;
if (hist_data->key_size > HIST_KEY_SIZE_MAX) {
ret = -EINVAL;
goto out;
......@@ -1419,7 +1757,8 @@ hist_trigger_entry_print(struct seq_file *m,
for (i = 1; i < hist_data->n_vals; i++) {
field_name = hist_field_name(hist_data->fields[i], 0);
if (hist_data->fields[i]->flags & HIST_FIELD_FL_VAR)
if (hist_data->fields[i]->flags & HIST_FIELD_FL_VAR ||
hist_data->fields[i]->flags & HIST_FIELD_FL_EXPR)
continue;
if (hist_data->fields[i]->flags & HIST_FIELD_FL_HEX) {
......
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